1. Field of the Invention
The present invention relates to an apparatus having two dials.
2. Description of the Prior Art
Dual dials are used in various apparatuses for size reduction. For example, in a camera where it is typical to set various kinds of information prior to photographing, a dual dial is used as an information setting means. Referring to FIG. 1, there is shown a conventional dual dial used in a camera. A first dial knob 22, a first inner dial 30, a dial bearing 29, an encoding plate 25 and a dial holding plate 27 constitute a shutter speed changing mechanism. The first inner dial 30 with click holes 34 has its upper part housed in the first dial knob 22 and is fixed to the first dial knob 22 by a screw 50. A shaft 30a of the first inner dial 30 is inserted into a hole 29a of the dial bearing 29 to abut the upper surface of the dial holding plate 27. The dial holding plate 27 is attached by a screw 28 which is inserted from the lower surface of the plate 27. Consequently, when the first dial knob 22 is rotated, the dial holding plate 27 is also rotated, so that a dial contact 41 attached to the dial holding plate 27 slides on an encoding pattern (not shown) formed on the lower surface of the encoding plate 25, thereby changing the shutter speed of the camera.
Since a click ball 32 held in a hole 29b of the dial bearing 29 with a spring 51 therebetween so as to be partly exposed out of the hole 29b engages with the click holes 34 provided in the first inner dial 30, the first inner dial 30 is rotated with clicks when the first dial knob 22 is rotated. Each click position corresponds to a predetermined shutter speed.
A second dial knob 23, a second inner dial 31, an encoding plate 26 and a base plate 24 constitute a camera on/off mechanism. In this case, a protrusion 36 extending downward from the second dial knob 23 engages with a concave 36' formed at a periphery of the second inner dial 31. To the lower surface of the second inner dial 31, a second dial contact 42 is attached, and a hole (not shown) for holding a spring 52 and a click ball 33 therein is formed on the lower surface. The click ball 33 selectively engages with one of the click holes 35 of the base plate 24 through an arched cut 53 of the encoding plate 26. Consequently, when the second dial knob 23 is rotated, the second inner dial 31 is also rotated with clicks. At this time, the second dial contact 42 slides on an encoding pattern 44 formed on the encoding plate 26.
The base plate 24 is fixed to the camera body. The encoding plates 26 and 25 are arranged so that the plate 26 is above the plate 25 with the plate 24 therebetween. Reference numeral 21 represents an outer cover of the camera. The second dial knob 23, the outer cover 21, the second inner dial 31, the base plate 24 and the dial holding plate 27 each has a necessary hole in their centers as shown in the figure.
However, since the above-described conventional dual dial requires a large number of parts, the assembling efficiency is low and it is cumbersome to manage such a large number of parts. As a result, the cost increases.